A Foreign Office spokesman said:
"We are aware that a British national has been reported missing in Queensland, Australia.
"Consular staff in Brisbane are in contact with Australian police who are conducting the search.
"We are providing consular assistance to the family in the UK at this difficult time."
More top news
A 24-year-old man has been arrested on suspicion of murder after the body washed up on the Thames shoreline.
Seven people have now been arrested after a man died from serious head injuries
The 38-year-old officer was on his way home from a night shift when he collapsed. His death is not being treated as suspicious.